abi

package
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 Go to latest Published: Mar 5, 2020 License: GPL-3.0 Imports: 14 Imported by: 0

Documentation

Overview

Package abi implements the Ethereum ABI (Application Binary Interface).

The Ethereum ABI is strongly typed, known at compile time and static. This ABI will handle basic type casting; unsigned to signed and visa versa. It does not handle slice casting such as unsigned slice to signed slice. Bit size type casting is also handled. ints with a bit size of 32 will be properly cast to int256, etc.

Index

Examples

Constants

View Source 
const (
	IntTy byte = iota
	UintTy
	BoolTy
	StringTy
	SliceTy
	ArrayTy
	TupleTy
	AddressTy
	FixedBytesTy
	BytesTy
	HashTy
	FixedPointTy
	FunctionTy
)

Type enumerator

Variables

View Source 
var (
	// MaxUint256 is the maximum value that can be represented by a uint256
	MaxUint256 = big.NewInt(0).Add(
		big.NewInt(0).Exp(big.NewInt(2), big.NewInt(256), nil),
		big.NewInt(-1))
	// MaxInt256 is the maximum value that can be represented by a int256
	MaxInt256 = big.NewInt(0).Add(
		big.NewInt(0).Exp(big.NewInt(2), big.NewInt(255), nil),
		big.NewInt(-1))
)

Functions

func ReadFixedBytes 

func ReadFixedBytes(t Type, word []byte) (interface{}, error)

ReadFixedBytes uses reflection to create a fixed array to be read from

func ReadInteger 

func ReadInteger(typ byte, kind reflect.Kind, b []byte) interface{}

ReadInteger reads the integer based on its kind and returns the appropriate value

func ToCamelCase 

func ToCamelCase(input string) string

ToCamelCase converts an under-score string to a camel-case string

func U256 

func U256(n *big.Int) []byte

U256 converts a big Int into a 256bit EVM number.

Types

type ABI 

type ABI struct {
	Constructor Method
	Methods     map[string]Method
	Events      map[string]Event
}

The ABI holds information about a contract's context and available invokable methods. It will allow you to type check function calls and packs data accordingly.

func JSON 

func JSON(reader io.Reader) (ABI, error)

JSON returns a parsed ABI interface and error if it failed.

Example 
const definition = `[{"constant":true,"inputs":[{"name":"","type":"address"}],"name":"isBar","outputs":[{"name":"","type":"bool"}],"type":"function"}]`

abi, err := JSON(strings.NewReader(definition))
if err != nil {
	panic(err)
}
out, err := abi.Pack("isBar", common.HexToAddress("01"))
if err != nil {
	panic(err)
}

fmt.Printf("%x\n", out)

Output:

1f2c40920000000000000000000000000000000000000000000000000000000000000001

func (*ABI) EventByID 

func (abi *ABI) EventByID(topic common.Hash) (*Event, error)

EventByID looks an event up by its topic hash in the ABI and returns nil if none found.

func (*ABI) MethodById 

func (abi *ABI) MethodById(sigdata []byte) (*Method, error)

MethodById looks up a method by the 4-byte id returns nil if none found

func (ABI) Pack 

func (abi ABI) Pack(name string, args ...interface{}) ([]byte, error)

Pack the given method name to conform the ABI. Method call's data will consist of method_id, args0, arg1, ... argN. Method id consists of 4 bytes and arguments are all 32 bytes. Method ids are created from the first 4 bytes of the hash of the methods string signature. (signature = baz(uint32,string32))

func (*ABI) UnmarshalJSON 

func (abi *ABI) UnmarshalJSON(data []byte) error

UnmarshalJSON implements json.Unmarshaler interface

func (ABI) Unpack 

func (abi ABI) Unpack(v interface{}, name string, data []byte) (err error)

Unpack output in v according to the abi specification

func (ABI) UnpackIntoMap 

func (abi ABI) UnpackIntoMap(v map[string]interface{}, name string, data []byte) (err error)

UnpackIntoMap unpacks a log into the provided map[string]interface{}

type Argument 

type Argument struct {
	Name    string
	Type    Type
	Indexed bool // indexed is only used by events
}

Argument holds the name of the argument and the corresponding type. Types are used when packing and testing arguments.

func (*Argument) UnmarshalJSON 

func (argument *Argument) UnmarshalJSON(data []byte) error

UnmarshalJSON implements json.Unmarshaler interface

type ArgumentMarshaling 

type ArgumentMarshaling struct {
	Name         string
	Type         string
	InternalType string
	Components   []ArgumentMarshaling
	Indexed      bool
}

type Arguments 

type Arguments []Argument

func (Arguments) LengthNonIndexed 

func (arguments Arguments) LengthNonIndexed() int

LengthNonIndexed returns the number of arguments when not counting 'indexed' ones. Only events can ever have 'indexed' arguments, it should always be false on arguments for method input/output

func (Arguments) NonIndexed 

func (arguments Arguments) NonIndexed() Arguments

NonIndexed returns the arguments with indexed arguments filtered out

func (Arguments) Pack 

func (arguments Arguments) Pack(args ...interface{}) ([]byte, error)

Pack performs the operation Go format -> Hexdata

func (Arguments) PackValues 

func (arguments Arguments) PackValues(args []interface{}) ([]byte, error)

PackValues performs the operation Go format -> Hexdata It is the semantic opposite of UnpackValues

func (Arguments) Unpack 

func (arguments Arguments) Unpack(v interface{}, data []byte) error

Unpack performs the operation hexdata -> Go format

func (Arguments) UnpackIntoMap 

func (arguments Arguments) UnpackIntoMap(v map[string]interface{}, data []byte) error

UnpackIntoMap performs the operation hexdata -> mapping of argument name to argument value

func (Arguments) UnpackValues 

func (arguments Arguments) UnpackValues(data []byte) ([]interface{}, error)

UnpackValues can be used to unpack ABI-encoded hexdata according to the ABI-specification, without supplying a struct to unpack into. Instead, this method returns a list containing the values. An atomic argument will be a list with one element.

type Event 

type Event struct {
	// Name is the event name used for internal representation. It's derived from
	// the raw name and a suffix will be added in the case of a event overload.
	//
	// e.g.
	// There are two events have same name:
	// * foo(int,int)
	// * foo(uint,uint)
	// The event name of the first one wll be resolved as foo while the second one
	// will be resolved as foo0.
	Name string
	// RawName is the raw event name parsed from ABI.
	RawName   string
	Anonymous bool
	Inputs    Arguments
}

Event is an event potentially triggered by the EVM's LOG mechanism. The Event holds type information (inputs) about the yielded output. Anonymous events don't get the signature canonical representation as the first LOG topic.

func (Event) ID 

func (e Event) ID() common.Hash

ID returns the canonical representation of the event's signature used by the abi definition to identify event names and types.

func (Event) Sig 

func (e Event) Sig() string

Sig returns the event string signature according to the ABI spec.

Example 

event foo(uint32 a, int b) = "foo(uint32,int256)"

Please note that "int" is substitute for its canonical representation "int256"

func (Event) String 

func (e Event) String() string

type Method 

type Method struct {
	// Name is the method name used for internal representation. It's derived from
	// the raw name and a suffix will be added in the case of a function overload.
	//
	// e.g.
	// There are two functions have same name:
	// * foo(int,int)
	// * foo(uint,uint)
	// The method name of the first one will be resolved as foo while the second one
	// will be resolved as foo0.
	Name string
	// RawName is the raw method name parsed from ABI.
	RawName string
	Const   bool
	Inputs  Arguments
	Outputs Arguments
}

Method represents a callable given a `Name` and whether the method is a constant. If the method is `Const` no transaction needs to be created for this particular Method call. It can easily be simulated using a local VM. For example a `Balance()` method only needs to retrieve something from the storage and therefore requires no Tx to be send to the network. A method such as `Transact` does require a Tx and thus will be flagged `false`. Input specifies the required input parameters for this gives method.

func (Method) ID 

func (method Method) ID() []byte

ID returns the canonical representation of the method's signature used by the abi definition to identify method names and types.

func (Method) Sig 

func (method Method) Sig() string

Sig returns the methods string signature according to the ABI spec.

Example 

function foo(uint32 a, int b) = "foo(uint32,int256)"

Please note that "int" is substitute for its canonical representation "int256"

func (Method) String 

func (method Method) String() string

type Type 

type Type struct {
	Elem *Type
	Kind reflect.Kind
	Type reflect.Type
	Size int
	T    byte // Our own type checking

	// Tuple relative fields
	TupleRawName  string   // Raw struct name defined in source code, may be empty.
	TupleElems    []*Type  // Type information of all tuple fields
	TupleRawNames []string // Raw field name of all tuple fields
	// contains filtered or unexported fields
}

Type is the reflection of the supported argument type

func NewType 

func NewType(t string, internalType string, components []ArgumentMarshaling) (typ Type, err error)

NewType creates a new reflection type of abi type given in t.

func (Type) String 

func (t Type) String() (out string)

String implements Stringer

Source Files

View all Source files

Directories

Path Synopsis
Package bind generates Ethereum contract Go bindings.
 Package bind generates Ethereum contract Go bindings.
backends

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